NSF Postdoctoral Fellow · Yale University, Malaker Lab · Evolutionary Genetics & Glycoproteomics · New Haven, CT
Petar Pajic Petar Pajic, currently an NSF Postdoctoral Fellow at Yale University, has published a new review article in Genome Biology and Evolution exploring how VNTRs drive evolutionary innovation in mammals while carrying functional risk.
Petar Pajic Understanding genomic function has historically relied on sequence conservation across evolutionary time. However, functional innovations often arise from rapidly evolving, nonconserved elements. Variable number tandem repeats (VNTRs) act as engines of both functional innovation and phenotypic consequence, influencing gene regulation, protein structure, and phenotypic diversity. This review synthesizes emerging insights into the functional and evolutionary impact of VNTRs in mammals, outlining the mutational mechanisms driving their evolution, the selective forces maintaining structural heterogeneity, and a theoretical framework for their persistence through evolutionary tradeoffs.
Petar Pajic The secretory calcium-binding phosphoprotein (SCPP) gene family, which includes genes expressed abundantly in human saliva, evolved alongside major evolutionary milestones in vertebrates. We explored the evolution of saliva-related SCPP genes using genomic and transcriptomic resources, finding previously undocumented convergent gene duplications in primate genomes. These saliva-related genes show signatures of positive selection while neighboring genes remain conserved, suggesting dietary and pathogenic pressures drove adaptive diversification of saliva composition in primates, including humans.
Petar Pajic I've been awarded a prestigious Postdoctoral Research Fellowship in Biology (PRFB) from the National Science Foundation, joining Dr. Stacy Malaker's lab at Yale University to study glycoproteomics and the evolutionary genetics of mucins.
Petar Pajic SARS-CoV-2 virus-like particles (VLPs) are ~100-nm bioinspired mimetics of the authentic virus, engineered here as a platform for mRNA delivery. A three-plasmid VLP system displayed ~7-fold higher viral entry efficiency than four-plasmid co-transfection, transducing over 90% of human ACE2-expressing cells. Viral tropism could be reprogrammed by swapping glycoproteins from other viral strains, and VLPs carried up to four transgenes, including functional Cas9 mRNA for genome editing, with successful delivery to mouse lungs.
Petar Pajic My latest paper on the evolutionary history of the AMY1 gene has garnered significant attention from CNN, The New York Times, and scientists in the field, shedding light on how our ancestors adapted to carbohydrate-rich diets long before the advent of agriculture.
Petar Pajic Human adaptation to a wide range of diets is a hallmark of our species, sometimes even reflected in our genomic diversity. The amylase gene encodes an enzyme that digests starch, a complex carbohydrate found in many modern human diets. Genomic studies have found substantial variation in the number of amylase gene copies, believed to be an adaptive response to dietary changes among human populations after the advent of agriculture. We reconstruct the locus's evolutionary history, tracing duplications that predate agriculture and seeded modern structural variation.
Petar Pajic Starch digestion is a cornerstone of human nutrition, and the amylase enzyme plays a key role in starch metabolism. The copy number of the human amylase gene (AMY1) has been associated with metabolic diseases and adaptation to agricultural diets. We show that amylase gene duplications originated over 700,000 years ago, predating the human-Neanderthal divergence, and likely primed the locus for rapid dietary adaptation during the agricultural transition through nonallelic homologous recombination.
Petar Pajic When I first entered Dr. Gokcumen's lab, I carried with me a heavy bag of naivety about the value of basic science. One story about the Manhattan Project reshaped my perspective on applied versus basic research entirely.
Petar Pajic Chemosensation (olfaction, taste) is essential for detecting and assessing foods, such that dietary shifts elicit evolutionary changes in vertebrate chemosensory genes. We explore the effects of subsistence behaviors on olfactory and taste receptor genes among rainforest foragers and neighboring agriculturalists in Africa and Southeast Asia, analyzing 378 functional OR and 26 functional TASR genes across 133 individuals. We find no evidence of relaxed selection in agricultural populations but identify subsistence-related signatures of local adaptation within each geographic region.